linux-kernel - [PATCH drm-dp 09/10] drm/hisilicon/hibmc: fix HPD no showing with VGA para of GRUB

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Message-ID: <20250530095432.1206966-10-shiyongbang@huawei.com>
Date: Fri, 30 May 2025 17:54:31 +0800
From: Yongbang Shi <shiyongbang@...wei.com>
To: <xinliang.liu@...aro.org>, <tiantao6@...ilicon.com>,
	<maarten.lankhorst@...ux.intel.com>, <mripard@...nel.org>,
	<tzimmermann@...e.de>, <airlied@...il.com>, <daniel@...ll.ch>,
	<kong.kongxinwei@...ilicon.com>
CC: <liangjian010@...wei.com>, <chenjianmin@...wei.com>,
	<lidongming5@...wei.com>, <libaihan@...wei.com>, <shenjian15@...wei.com>,
	<shaojijie@...wei.com>, <jani.nikula@...ux.intel.com>,
	<dmitry.baryshkov@....qualcomm.com>, <dri-devel@...ts.freedesktop.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH drm-dp 09/10] drm/hisilicon/hibmc: fix HPD no showing with VGA para of GRUB

From: Baihan Li <libaihan@...wei.com>

In early OS versions， there is a bug in hibmc-drm driver previously,
so some OS add a VGA parameter in GRUB(video=VGA-1:640x480-32@...e) to
fix the bug, that will config a force VGA mode to drm driver. However, the
HPD problem exists that mentioned in previous patch, so change VGA's status
in force() to compatible with some older OS versions.

Fixes: f9698f802e50 ("drm/hisilicon/hibmc: Restructuring the header dp_reg.h")
Signed-off-by: Baihan Li <libaihan@...wei.com>
---
 drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c
index 73dd3d5fc26c..d609ccda2f2a 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c
@@ -61,6 +61,19 @@ static int hibmc_vdac_detect(struct drm_connector *connector, struct drm_modeset
 	return connector_status_connected;
 }
 
+static void hibmc_vdac_force(struct drm_connector *connector)
+{
+	struct hibmc_drm_private *priv = to_hibmc_drm_private(connector->dev);
+	struct hibmc_dp *dp = &priv->dp;
+
+	if (dp->hpd_status) {
+		connector->status = connector_status_disconnected;
+		return;
+	}
+
+	connector->status = connector_status_connected;
+}
+
 static void hibmc_connector_destroy(struct drm_connector *connector)
 {
 	struct hibmc_vdac *vdac = to_hibmc_vdac(connector);
@@ -81,6 +94,7 @@ static const struct drm_connector_funcs hibmc_connector_funcs = {
 	.reset = drm_atomic_helper_connector_reset,
 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+	.force = hibmc_vdac_force,
 };
 
 static void hibmc_encoder_mode_set(struct drm_encoder *encoder,
-- 
2.33.0